Dear Dr Scot Bobby,
Thank you very much for including me in your mail address.
In your excellent comments, I noticed your view on information derived from epidemiological studies of A-bomb survivors. I thought you might be interested in the attached viewgraph:
This presentation was originally prepared for the Vi International Conference Chernobyl Catastrophe: Estimation of Health Consequences, Ecological, Social and Economical Risks September 21 - 26, 2008, Kiev, Ukraine.
Unfortunately, the conference was cancelled at the last minutes and I have never used this.
Genn Saji
_________________________________________________________________________________________________
On 2012/05/10, at 6:02, Scott, Bobby wrote:
> Dear Dr. Parthasarathy,
>> I have accessed the website you indicated related to the Bulletin of Atomic Scientist Special Issue: Low-Level Radiation Risks. However, accessing the special issue publications (full papers) requires a fee for each paper while the abstracts were available without cost. Thus, my comments below are based on the abstracts.
>> If the objective of the Special Issue is to equip members of the public with broad information on the effects of low-level radiation, then the publication in my opinion is a failure. The paper by Jan Beyea titled “The scientific jigsaw puzzle: Fitting the pieces of the low-level radiation debate” is quite misleading based on the abstract. For example she states the following: “Model fits … to the atomic-bomb data support a linear no-threshold model, below 0.1 Sv. On the basis of biologic arguments, the scientific establishment in the United States and many other countries accepts this dose-model down to zero-dose, but there is spirited dissent. The dissent may be irrelevant for developed countries, given the increase in medical diagnostic radiation that has occurred in recent decades; a sizable percentage of this population will receive cumulative doses from the medical profession in excess of 0.1 Sv, making talk of a threshold or other sublinear response below that dose moot for future releases from nuclear facilities or a dirty bomb.”
>> Modern radiation molecular and cellular biology does not support the linear-no-threshold (LNT) model. It is now recognized by many scientists that there is a hierarchy of protective mechanisms that are activated by low doses of low-LET and low- plus high-LET radiation that include DNA damage repair, apoptosis of severely damaged cells, removal of already-present aberrant cells via apoptosis (stress response; regulated by intercellular communication between aberrant and normal cells), and removal of pre-cancer and cancer cells via stimulated anticancer immunity. The French Academies report related to LNT, which was discounted by Jan Beyea and other LNT advocates, discussed these protective processes and took them into consideration when concluding that LNT was not supported by data for low-LET doses < 100 mGy. In contrast, the BEIR VII Report discussed these protective processes and then ignored their very important implications when recommending continued use of the LNT model. Our research has recently uncovered a novel protective mechanism whereby low-dose gamma rays suppress cigarette-smoke-carcinogen-induced neoplastic transformation and presumably also smoking related lung cancer. The protective mechanism relates to gamma-ray suppression of cigarette-smoke-carcinogen-related inflammatory cytokines released by stromal cells that promote the neoplastic transformation of normal human bronchial epithelial cells (Chen W. et al., 2012, Carcinogenesis; prepress abstract available at http://www.ncbi.nlm.nih.gov/pubmed/22556270 ). We also have new data showing that repeated low doses of gamma rays can prevent cigarette-smoke-carcinogen-induced lung tumors (adenomas) in mice and also appear to prevent the occurrence of spontaneous hyperplastic foci in the mouse lung (Bruce V., et al., Dose-Response 2012 Conference presentation).
>> The protective processes indicated above are thought to be regulated via epigenetic mechanisms and epigenetic changes appear to be orders of magnitude more likely than radiation-induced mutations when the radiation dose is low (Scott BR. 2012. First generation stochastic gene episilencing (Step1) model and applications to in vitro carcinogen exposure. Dose-Response, prepress version available at www.Dose-Response.com).
>> The Special Issue paper by David Richardson titled “Lessons from Hiroshima and Nagasaki: The most exposed and most vulnerable” relied on information derived from epidemiological studies of A-bomb survivors. In the abstract it is stated that cancer risk estimates are likely underestimated since frail people were lost to follow-up shortly after the bombings in Hiroshima and Nagasaki. As with other studies of these populations, the researcher failed to realize that the Japanese victims were exposed to multiple insults (radiation + blast wave + thermal wave + other) and had to reside and survive in war torn cities. No adjustments have been made for the combined exposure and high stress environment so that cancer risks are likely to be overestimated, even for high doses since all harm is attributed to radiation. Further, new information discussed by Mohan Doss at the Dose-Response 2012 conference indicated that serious bias in the baseline cancer rate due to year-to-year variation for the indicated populations likely altered the shape of the dose-response curve for cancer induction from nonlinear (e.g., threshold or hormetic type) to apparently linear.
>> The Special Issue assigned more credibility to the BEIR VII Report than to the corresponding French Academies Report. The BEIR VII Report however relied essentially on epidemiological studies while the French Academies Report gave considerable weight to findings from basic research. Regarding relying on epidemiological studies, there is growing evidence that procedures employed in studies of radiation-associated cancer can change real threshold- and hormetic-type dose-response relationships into what appears to be an LNT type dose response. Some of these procedures are summarized below:
>> 1. Applying standard risk factor adjustments in the hormetic zone where cancer risk is suppressed by radiation adaptive responses (e.g., preventing smoking related lung cancer via radiation activated natural protective processes). The indicated adjustments appears to add back cancer risk (e.g., from smoking) that was eliminated by the body’s protective mechanisms that were activated by low-dose radiation (Scott BR. Dose-Response 9:444-464, 2011; freely available at www.Dose-Response.com ).
>> 2. Not eliminating bias associated with year-to-year variation in the baseline cancer rate (Doss M. Dose-Response 2012 Conference presentation).
>> 3. Dose lagging (throwing away parts of the low doses involved in stimulating the body’s natural defenses and parts of the high doses involved in immune system suppression) shifting the dose-response curve to the left (Scott B.R. et al., Journal American and Physicians and Surgeons 13:8-11, 2008; freely available at http://www.jpands.org/vol13no1/scott.pdf ).
>> 4. Assuming a non-existent healthy worker effect when and adaptive response actually occurs (Fornalski K.W. and Dobrzynski L. Dose-Response 8(2):125-147, 2010; freely available at www.Dose-Response.com ).
>> 5. Averaging over large dose intervals when evaluating relative risk (RR) or excess relative risk (ERR) and thereby eliminating a threshold dose or hormetic zone (Scott et al. 2008; Thompson R.E., et al. Health Physics 94(3):228-241, 2008; Thompson R.E., Dose-Response 9(1):59-75, 2011, freely available at www.Dose-Response.com ).
>> 6. Inclusion of high-dose data where significant immune system suppression occurs (Shan Y-X, et al., Radiation and Environmental Biophysics 46:21-29, 2007) that can significantly increase the cancer risk, when fitting the LNT function to data that includes low-dose, adaptive-response data that do not support the LNT hypothesis (Scott et al. 2008).
>> Advocates of LNT have caused many radiation-phobia related casualties (e.g., following Chernobyl where > 100,000 abortions of wanted babies were reported by Linda Ketchum in 1987 [Journal of Nuclear Medicine 28:933-942, 1987] to have occurred in Eastern Europe). LNT-promoted casualties have also occurred in Japan related Fukushima. Many of the evacuees are now under enormous stress and are suffering from psychological problems related to their state of hopelessness (Genn Saji, personal communications). In addition, apparently based in part on advice from LNT-hypothesis advocates, Japan is currently running on 0% nuclear power, which will likely lead to a very high financial cost to the Japanese people related to having to use alternative energy sources.
>> Sincerely,
> Bobby R. Scott
> LRRI, Albuquerque, NM, USA
>> From: parthasarathy k s [mailto:ksparth at yahoo.co.uk]
> Sent: Wednesday, May 02, 2012 9:29 PM
> To: The International Radiation Protection( Health Physics) Mailing List
> Cc: Scott, Bobby; stewart farber; Mike (DOH) Brennan
> Subject: Special issue of the Bulletin of Atomic Scientists
>> Dear Dr Scot Bobby,
>> I hope you had a chance to have a quick look at the recently (May 1st, 2012) issued special issue of the Bulletin of Atomic Scientists covering effects of low level radiation.
>> You can access it at:
>http://bos.sagepub.com/content/current> I shall greatly appreciate your critical appraisal of the issue.
> …
> Regards
> Parthasarathy
>>>> *******************************************************************************
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